SCIENCE & TECHNOLOGY
from the SCENEs A selection of stories from C&EN’s six online TOPICAL NEWS CHANNELS
SMALL MOLECULES REACTIVATE RECEPTOR LINKED WITH SCHIZOPHRENIA Medicinal chemists have designed small molecules that can restore activity to a malfunctioning glutamate receptor linked to schizophrenia (ACS Chem. Biol. 2014, DOI: 10.1021/cb500560h). The compounds could be a first step toward personalized therapeutics for people with schizophrenia
FROM THE MATERIALS SCENE
STRONG, SPRINGY MATERIALS MADE IN THE FREEZER
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who carry the mutations glutamate, mGlu1’s N N behind the dysfunctional natural ligand. To try H Cl protein. Previous reto make the mutant O This molecule can search had found that some receptors respond restore the function people with schizophrenia and normally, the chemother psychiatric disorders carry mu- of mutated glutamate ists designed a series receptors linked to tations in the gene for metabotropic of molecules based schizophrenia. glutamate receptor subtype 1, or on ligands for a mGlu1. Craig W. Lindsley of Vanderrelated glutamate rebilt University and his team expressed nine ceptor. Two of these compounds rescued versions of this receptor, each carrying the function of all nine receptors to varying one of the mutations, in human cells. The degrees. And one had promising pharmamutations caused the proteins to produce cokinetic properties and could cross the muted responses to the neurotransmitter blood-brain barrier when tested in rats.
cross-linker. As ice crystals grow, the particles move to the crystal boundaries. The polymer forms a 10-nm-thick film around the particles and then gets cross-linked in the frozen state. Finally, the researchers thaw the mixture to produce the porous elastic materials. The team made composites using both 300-nm- and 1-µm-diameter silica
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A one-step freezing method yields strong, porous inorganic materials that can spring back after being squeezed to 15% of their original size (Chem. Mater. 2014, DOI: 10.1021/ cm502643a). Such ultralight, compressible materials could find use in tissue engineering scaffolds, biomedical implants, and electronics, say the researchers who synthesized them. The new materials—composites of rigid particles dispersed in a three-dimensional web A springy, porous material made by ice of an organic polymer—are templating consists of 1-µm silica particles made using a simple proembedded in a polyethyleneimine matrix, as seen cess called ice templating. in these scanning electron micrographs. The researchers, led by Guruswamy Kumaraswamy and Sayam Sen Gupta of India’s Counparticles in polyethyleneimine, as cil on Scientific & Industrial Research, well as a biocompatible material using freeze a mixture of the particles, the 300-nm-wide hydroxyapatite particles polymer, and a poly(ethylene glycol) in gelatin.
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NANOPARTICLES REGULATE GENE EXPRESSION Researchers have decorated gold nanoparticles with peptides and a polyamide to impart them with all the natural functions of a transcription factor (ACS Nano 2014, DOI: 10.1021/ nn501589f). The team hopes to use these artificial transcription factors to program stem cells to create specific tissues or to revert cells back to earlier developmental states. KiBum Lee of Rutgers University, Piscataway, and his team designed the particles, called NanoScripts, starting with a 9-nm-diameter gold core. After coating the gold with mercaptoundecanoic acid, they used amide coupling to attach the peptides and polyamide. One peptide helps the particles enter a cell’s nucleus, the polyamide helps the NanoScripts bind to a DNA sequence associated with a target gene, and a second peptide recruits RNA polymerase and other proteins involved in gene transcription. Human cells treated with the NanoScripts expressed a reporter gene at levels 15-fold that of cells treated with naked gold nanoparticles. Meanwhile, cells treated with free polyamide and polymerase-recruiting peptide, not attached to the gold core, showed just a 2.2-fold increase in expression.
SEPTEMBER 29, 2014
